This disclosure relates to polyester polycarbonate compositions, methods of making them, and articles formed therefrom.
Polyesters can be blended with other miscible or immiscible polymers to improve various properties of the polyester. Specifically, polyesters can be blended with polycarbonates to provide improved mechanical properties such as impact strength, and/or can also be added to improve rheological properties such as melt volume rate. However, other properties of the polyester, specifically optical properties, can be adversely affected by forming a blend. Such polyester blends can have a hazy appearance, with diminished light transmittance. Miscible blends, that is, blends that have substantially a single phase, tend to have less haze. It has been difficult, however, to develop blends of polyesters and polycarbonates that have sufficient miscibility to provide good optical properties, while maintaining other advantageous properties of the blends.
There accordingly remains a need in the art for miscible polyester polycarbonate compositions comprising polycarbonate and polyester, in particular polyester polycarbonate compositions having high transparency and low haze. It would be a further advantage if the compositions had other advantageous properties such as weatherability, barrier and chemical resistance